Direct sonochemical preparation of high-surface-area nanoporous ceria and ceria–zirconia solid solutions

High-quality bulk single crystals of pure and Er3+-doped SrLaGa3O7 (SLGO) were grown successfully by the Czochralski method. The crystal structure of SLGO was demonstrated. The theoretical calculations based on density functional theory methods were carried out on the SLGO crystal. Its band structure and density of state were presented. The absorption, up-conversion, near-infrared and mid-infrared fluorescence spectra, as well as the fluorescence decay curves of Er: 4I13/2 and 4I11/2 levels of the Er:SLGO crystal were measured at room temperature. The spectroscopic properties including the absorption and emission cross sections as well as the fluorescence lifetimes were revealed. It is concluded that the Er:SLGO crystal is a promising candidate material for achievement of a mid-infrared laser.

Bulk Crystal Growth, First-Principles Calculation, and Optical Properties of Pure and Er3+-Doped SrLaGa3O7 Single Crystals

A review of lithium niobate single crystals and polycrystals in the form of powders has been prepared. Both the classical and recent literature on this topic are revisited. It is composed of two parts with sections. The current part discusses the earliest developments in this field. It treats in detail the basic concepts, the crystal structure, some of the established indirect methods to determine the chemical composition, and the main mechanisms that lead to the manifestation of ferroelectricity. Emphasis has been put on the powdered version of this material: methods of synthesis, the accurate determination of its chemical composition, and its role in new and potential applications are discussed. Historical remarks can be found scattered throughout this contribution. Particularly, an old conception of the crystal structure thought as a derivative structure from one of higher symmetry by generalized distortion is here revived.

https://www.mdpi.com/2073-4352/10/11/990/pdf

Lithium Niobate Single Crystals and Powders Reviewed—Part I

Growth and properties of Ru-doped lithium niobate crystal

Lithium niobate (LiNbO3 or LN) and lithium tantalate (LiTaO3 or LT) crystals, which have been widely applied in many fields such as electro-optics, birefringence, nonlinear optics, photorefraction, piezoelectricity and other areas, are reviewed. The studies of the properties and growth techniques are reviewed to give a brief idea of the growth of LN and LT crystals with high quality. The anti-site defects of these crystal materials have been accepted as one of the key factors constraining the improvement of their properties. This review shows the simulated calculation and structure of anti-site defects in LN/LT crystals and their effect on the physical properties and summarizes the recent progress in theoretical and technical processes, including the improved applications. We reviewed two main methods for the elimination of anti-site defects: doping of metal ions and growth of stoichiometric crystals. Finally, the prospects for future studies are outlined.

Formation mechanism and elimination methods for anti-site defects in LiNbO3/LiTaO3 crystals

Single crystals of lithium niobate doped with 0.03 and 0.1 at.% of Cu or Fe ions were grown by the Czochralski technique. Optical absorption spectra in visible and infrared regions before and after • irradiation with doses up to 10 5 Gy were measured and positions of both dopants in LiNbO 3 lattice were analyzed according to changes in optical absorption in the range of OH group absorption. Some properties of crystals doped with Cu during the growth processes were compared to those for specimens doped by thermodiffusion. It was observed that doping with Cu results in an increase of crystal resistance to radiation.

http://www.skaczmarek.ps.pl/130-Growth-CRT-99.pdf

Growth and Characterization of LiNbO3 Single Crystals Doped with Cu and Fe Ions

Radiation defects in Dy3+ doped LiNbO3 single crystals

Rare-earth doped SrLaGa3O7 single crystal are promising laser materials. Also crystal doped with Ho3+ ions could be used as efficient laser in visible and near IR regions. Laser materials, generating in visible and IR regions, can be used for optical data recording in micro photolithography and in medicine. SrLaGa3O7 single crystal doped with 0.3, 1.5 and 2 at percent of Ho3+, respectively were grown by the Czochralski method with use of iridium crucible and after heater. According to EPMA measurements distribution coefficient of Ho3+ in SrLaGa3O7 was estimated to be k approximately equals 0.22. Optical absorption spectra in visible and IR regions were measured at 300K and 12K respectively. Optical quality of single crystals was checked by the use of computerized imaging spectropolarimeter and polariscopic measurements. Temperature dependence of capacitance and conductivity for different dopant concentrations were also measured.© (2001) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

B. Kaczmarek

Papers

Growth and Characterization of LiNbO3 Single Crystals Doped with Cu and Fe Ions

Radiation defects in Dy3+ doped LiNbO3 single crystals

Czochralski growth and characterization of SrLaGa 3 O 7 :Ho 3+ single crystals